单项选择题
Which of these technologies is characterized as being a multipoint Layer 2 VPN that connects two or more customer devices using Ethernet bridging techniques?（）
A.DPT B.MPLS C.VPLS D.CWDM E. DWDM F. SONET/SDH
多项选择题 Which two of these are characteristics of Metro Ethernet? （）
多项选择题 Which two of these Metro Internet services map to E-LAN services that are defined by the MEF?（）
多项选择题 Which three of these Metro Ethernet services map to E-Line services that are defined by the MEF?（）
